Limit regulator



March 31. 1925. 1,531,996

- 1-. STEIN LIMIT REGULATOR Filed May 28, 1923 Fig.4.

lll'IIIlI/lll IIIII Ifi/entori ThebdorfStein,

His Attorney.

Patented li/lar. 31, 1925. 1

UNITED STATES 1,5313% PATENT OFFICE.

THEODOR STEIN, OF SCHONEICHE, GT RMANY, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION 033 NEW YORK.

LIMIT REGULATOR.

Application filed May 28, 1923. SeriaI No. 641,984.

To all whom it may concern:

Be 1t known that I, Tnnonon STEIN, a citizen of the Republic ofSwitzerland, re-

siding at Schoneiche, Germany, have invented certain new and usefulImprovements in Limit Regulators, of which the following is aspecification.

This invention relates to automatic regulators which are employed tomaintain speed values, current values, pressure values and the likebetween certain predetermined limits.

More particularly this invention relates to automatic pressureregulators for centrifugal compressors which may be adjusted to maintainthe pressure values in the discharge conduit of such compressors betweenany desirable predetermined limits.

The object of this invention is to provide an improved regulator of theabove type which is positive andsensitive in operation, which has nolost or ineffective motion in its operating stroke and which is simplein structure and operation.

F or a consideration ofwhat I believe to be novel and my invention,attention is directed to the accompanying drawing, description andappended claims.

In the drawing, Fig.1 is a diagrannnatic view partly in section of oneembodiment.

of the invention as applied to'a centrifugal compressor installation;Fig. 2 is an enlarged view of the diagrammatic representation of theregulator shown in connection with Fig. 1; Figs. 3, 4i, 5 and 6 aresectional diagrammatic views of modifications of the form of theinvention shown in Fig. 2.

Referring to Figs. 1 and 2, a centrifugal compressor 7 having anintakeconduit- 8 and a. discharge conduit 9, is shown directly connectedwith an elastic fluid turbine 10. The

turbine is supplied with operating fiuidwire 12 to close a correspondingamount while an upward movement of the end 15 will cause the throttlevalve 12 to open a cc mir'ozidmg amount. As this device. is well knownin connectionwith elastic fluid be unnecessary;

In this particular installation with which it will be understood theinvention is shown only by way of example, it is assumed that thepressure in the discharge conduit 9 of the compressor 7 is to be keptwithin certain allowable limits, for example, between five atmospheresmaximum andone atmosphere minimum, by varying the speed of the turbineand hence the speed ofthe compressor and the pressure delivered by it tothe discharge conduit 9. To do: this automatically, a regulatorembodying the inventio'n is-inserted, as a connecting and controllinglink, between the pressure in the compressor discharge conduit 9 and thefree end 15 of the hydraulic gear control lever let, being mountedadjacent the latter in av hollow pedestal casing as shown at 16. j

A cylinder 17. formed at the upper end turbines further description isbelieved to of the casing 16 carries a movable abutment '18 and anactuating spring19 compressed between the l'atter and the upper end ofsaid cylinder. The actuating spring 19 tends to move the abutment 18down wardly against a pressure suppliedbeneath it through a pressureline 20 connected at one end with'the discharge conduit 9 of thecompressor, andatthe other end with the cylinder at a point sufficientlynear the lowor end of the latter to insure pressure heneath the movableabutment throughout its entire travel.

The surface area of the movable abutment 18 and the strength oftheactuating spring 19 are so proportioned relatively to each other thatthe movable abutment will as-. sumo anormal balanced position as shown,substantially midway between the ends of the cylinder when the pressure.below it reaches the upper allowable limit of five atmospheres, thispressure being just sufficient to balance the downward thrust of theactuating spring 19 with the movable abutment in this position.

Any increase or decrease in pressure will cause an unbalancing and atendency on the 'ia-rt of the abutment to move toa new position ofequilibrium, which movement is used to actuate the floating controllever 14.- of the hydraulic gear .13 to correct such increase ordecrease by a corresponding change in speed of the turbine. For thispurpose, the abutment 18 is provided with a rod 21 i extending axiallydownwardly from through the center of the pedestal casing and pivotallyconnected at a point 22- between its ends witlr one end of a horizontallever 23. This lever passes outwardl v through an opening 24 in thecasing to a point substantially vertically below the end 15 of thefloating control lever 14 and is connected therewith by a link 25 having a pivot at either end. The lever is pivotally mounted on ahorizontal and 26 carried by an ear 27 extending outward-- ly from thecasing adjacent the opening 24. This opening is of sullici'ent verticallength to permit a full operating swing of the lever 23.

The above described lever arrangement is such thatan upward movement ofthe abutment 18 will cause a corresponding downward movement of the end15 of the floating control lever 1-1, a corresponding closing of thethrottle valve 12 and, through the accompanying reduction of speed, acorresponding reduction in pressure in the dis charge conduit 9 of thecompressor while conversely a downward movement of the abutment 18 willcause a corresponding increase in pressure in said compressor dischargeconduit.

Because of fluctuations in the pressure of the motive fluid delivered tothe turbine, the speed and consequently the discharge pressure'of thecompressor willvary, and for any given speed "the pressure in thedischarge conduit will vary because the demand will usually increase anddecrease between wide extremes, hence to meet t uese conditionsordinarily requires a regulator vith an actuating member which travels aconsiderable distance between "effective op erating and controllingportions of its stroke, rendering such a regulator less sensitive thandesirable and of large dimensions 01' else requires the use of tworegulators, one for each pressure limit, resulting in a complicatedregulating means.

As a result of the present invention, however, one regulator serves tocontrol both limits and without any actuating control part thereofmoving between the limits, resulting in greater sensitivity and less complicated parts. This is accomplished according to the invention throughthe use of an auxiliary spring 28 seated in the bottom of the casing andcompressed beneath astop dislt 29 to such a degree that it biases saidstop disk upwardly againstan annular stop shoulder 80, formed in thecasing walls, with a force equal to the difference between that exertedagainst the actuating spring 19 by the movable abutment 118 when underthe influence of the lnaxinium allowable pres sure of live atmospheresand that when the same is under the influence of the minimum allowablepressure of one atmosphere. By

it means of rod 21., provided with a toot ill at its lower end arrangedto make contact with the disk 29 as soon as the pressure below themovable abutment 1S fails to bala ce the actuating spring above it, theat spring 28 receives tl'irough said rod anal the stop disk '29 thedownward thrust on the movable abutment resulting from such decrease inpressure below it and prevents it from moving until this pressure fallsto the lower limit of one atmosphere. lVith an further decrease inpressure below the abutment 18, the auxiliary spring 28 is unable tosupply the deficiency and begins to yield, allowing the abutment 18 tomove downwardl; and operate the throttle valve through the lever linkageas hereinbe'fore de- =1 7 This will bring about an increase in the speedof the turbine until the pressure again comes within the predeterminedlimits when the movable abutment returns to its normal position.

It will thus be seen that the auxiliary spring 28 is set to functionpassively as a holding means to prevent the movable abutment 18 frommoving downwardly from the normal position while the pressure in thedischarge conduit 9 remains above thelowcr predetermined limit of oneatmosphere. The actuating spring 19 presen the movable abutment fromn'ioving upwardly from said normal position while the pressure in thedischarge conduit 9 remains below the predetermined upper limit of livatmospueres, being set as hereinbefore described. to eXactly balance then'iovablc abutment in the normal position shown when the upper pressurelimit is reached, hence t throttle valve and the operation of the tu nois not subjected to continual operation or any hunting action while thePI'GSSLU'O in the discharge conduit oi the turbine remains between theselimits. ll the pressure in the conduit 9 does exceed the upper limit oilive atmospheres, the abutment will. he moved upwardly by such pressurewhich will over-balance the actuating spring pressure. The foot 31 ofrod 2l will leave the Stop disk 29 as the abutment moves upwardlyleaving the auxiliary spring 28 out of the action above this point.

1. his upward movement; of the movable abutment will cause a decrease inthe pressure delivered by the conupressor as described hereinlii As tothe setting of the i ulator 'lor given compressor installat in thepressure limits are decided upon and the upper or actuating spring 19 ischosen in relation to the surface area of the movable abut: ashereinbe'lore mentioned to receive and hold said movable abutment insubstantia ly the mid position shown, which is the normal position, whenthe upper limit of prc sn'c is reached, by moving the end 15 of thefloat ing control lever 14; to the proper position 'liarv to obtain thespeed required to produce this pressure, the distance between the outerend of the lever 23 and said end 15 then determines the length of thelink 25 to be inserted between them. This position of the movableabuti'nent also determines the length of the rod 21 extending downwardlyfrom it, as the :t'oot 31 at its lower end should be just on the pointof making contact with the stop disk .29 at this time. The auxiliaryspring is designed to hold the disk 29 against the stop shoulder 80 witha force sufficient to hold the movable abutment from moving until thepressure reaches the lower limit. Thus it is seen that the spring 28must be weaker than spring 19 and be able to resist the downward thrust.of the latter only when assisted by a pressure, supplied from thedischarge conduit f) beneath the abutment 18, of. a value in excess ofthe lower allowable pressure limit.

The regulator shown in Figs. 1 and 2 may be adapted without any materialchange to control a valve directly, as will be noted now in referring toFig. 3, in which the same reference numerals have been used as for likeparts in the preceding figures, except that the exponent b is added.

In this figure the regulator is shown mounted directly on a conduit 32and connected with a valve 33 within said conduit, which controls anopening 84 between a region of higher pressure 35 and a region of lowerpressure 36, the flow being in the direction oi? the arrow when thevalve is open. The region of higher pressure 8? n'iight, for example, beconnected with the discl'iargc conduit of a compressor while the regionor lower pressure 36 i'night lead to the atmosphere. In this case thevalve 53 would serve as a relief valve to maintain ,the pressure in thedischarge conduit of: said compressor between certain pressure limits.

The space below the movable abutment is is connected with the region ofhigher pressure through a pressure line 20" while the valve 33 connectedwith the movable abutment through an extension of the rod 21 indi ratedat 37. This extension is connected with the foot 31" of rod 21 andpasses through an opening 38 in stop disk In the form of the regulatorembodying the invention shown in Fig. ft in which reference numeralsused for similar parts in the preceding figure have been used with. theexponent 0 added, again it will be noted that no general departure fromthe construction of the preceding figures is made.

This is a regulator which is operated by changes in the flow of currentthrough an electrical circuit indicated at l0 instead of through changesof pressure in a fluid con duit. For this purpose a solenoid 41 is insorted in the circuit and adapted to move the abutment 18. The abutment18 is connected with a magnetic core 42 within the solenoid and isbiased upwardly with increasing force as the current flowing through thesolenoid increases to a predetermined upper limit, beyond which theopposing force of the actuating spring 19 is overcome and the movableabutment is carried upward a corresponding amount. A guide rod '43connected with the movable abutment and downward movement under theaction of the actuating spring 19 by the foot 31 of the rod 21 bearingagainst the stop disk 29 which in turn is held from downward movement byan auxiliary spring 28 compressed beneath it sulliciently to allow nomovement of said stop disk 29 until the current flow in circuit 40 andhence the upward pull oi the solenoid on the core 42 iialls to a certainlower predetermined limit, when on further decrease in the current fiow,spring 28 yields and permits the abutment 18 to move downwardlyactuating the current control-' ling device as pointed out above.

In Flg. 5 a departure from the form of the regulator employed in theprecedmg figures is shown by way of example to illus-' iii) trate theadaptability of the invention to various needs. A rearrangement of thecomponent parts oi the regulator of Fig. 2 is provided, these partsbearing the same number as like parts in Fig. 2 with the exponent dadded.

In this embodiment of the invention a casing 16 is divided into an upperchamber containing an auxiliary spring 28 and a lower chamber 46containing actuating spring 19. A wall ll? between the chambers servesas a seat for both springs.

The actuating spring 1S) is compressed between the i *all 4:? and amovable abutment 18 provided at one end of a hori'lsontal lever 48, tobias the abutment downwardly against a block which in turn rests on aflexible diaphragm The diaphragm covers an opening 51 in a casing inwhich exists a pressure the v: no of which is used to dete'mine theposition of a reb l valve 53. This valve is positioned over reliefopening 5 lthrough which a fluid direction of the arrows, s n'ially pa'tially open on the oppo the lever -18 from that of abutment lever ispivoted between its ends as cated at 55' and passes into the casingthrough an opening 56. The arrangement is such that an increase inpressur below the diaphragm will tend to how it upwardly to move theabutment 18 against the biasing action of spring 19. This in turn willcause a closing action of the valve as over the reliel o1 ening 5a.

The actuating spring 19 is designed hold the movable abutment 1S an'airta force exerted on the diaphragm until a certain predet rmined upperpressur vields roporis reached; above which it tionately to the excesspressure and r the valve to move toward the closed position over theopening Upon a decrease in pressure below the diaphragm 50, the movableabutment is prevented i roin moving downwardly to more fully open thevalve 53, by a rod 21 which extends from it axially upward through thecasing to a point just above a stop disk 29, openings 5'? and 58 beingprovided for it in wall at? and stop disl' respectively. At this iointjust above stop disk 29 a head 31 is formed on the rod and positionedrelative to the disk 29 so that it will malte contact with said dislrupon the least downward movement of the abutment 18 "from it uial,position shown. It. will be un that. the normal position is determinedby increasing the pressure below the diaphragm to the upperpredetermined limit, at which time the abutment will be balanced betweenthe pr ssure of the diaphragm 50 below and that of the actuatin spring19 above. The valve is then positioned on the end of lever l? to thedesired distance from the reopening 54: and the head or is then made tobe just on the point of making contact with the stop their 29 in thepreceding figures, the stop dis.- biaed by the auxiliary spring againsta stop shoulder provided at oi the casing", with a force which is su'iicient to hold the abutment 18 from downward movement until thepressure b neath it this case that eizisti n beneah be dia- (in c I l ccalve 5 controlled Y i2, being more ed proporti i as he pressure a casing52 code a certain predetermined higher value and being more fully openede asin 52 falls below l o iening while the grease to etween saidpredeterand lower limits.

T ucr .nuplished through one regulator 1 simple parts, and like th .3bed embodiments (If the invention represents but one oi? many regu- '0which the invention i may be adapted.

' ator appl 1O illustrate the extent to which the invention may beadapted to various control e vices to provide them with he limit feaewhich the invention embodies, in Fig. (3 revolving tly weight governoris shown eulbodying the invention. is in the preceein figures, parts ofthis figure have the same reference numerals with the exponent e addedas similar parts appearing through out the drawing.

hav- .g Y I the ends of two upper a1 n.- 0, 6O pivotally connected attheir upper central driving shaft 62.

The weights 59, 59 are acted upon by centrifugal tore, represented bythe ar rows, as they revolve and tend to move apart against the action(it a retracting spring 19 connected between them and so tcnsioned thatit will not peruiu them to move from the position shown, which is thenormal position, until a certain upper speed limit is rea :hed. With thespeed below this p a 4 upper limit this spr ng tends to overco o thecentrifugal fir-co acting on the 'i C weights and move them. together,but this is prevented until a certain lower limit oi: speed is reached,through a mi vable abutment 18 in the form of a sliding sleeve connectedwith each weight by a link 63 hearing downwardly on a stop disk Thisstop dislr is in turn held from downward movement by an auxiliary spring28 seated in the bottom of a hollow casing 16.

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This casing may be part of the mechanism with which the governor isassociated or a separate housing. It serves to support the shaft 62which. passes axially upwardly 'tl'irough it and is formed at its upperend with a stop shoulder 3O for the disk 29 i The auxiliary spring 28presses the stop diskupwardly against the stop shoulder 3O with a forcesufiicient to hold the downward hrust of the movable abutment 18 as thespeed decreases to a predetermined lower limit when it yields to thesuperior force of the spring 19 and permits the movable abutment l8 tomove downwardly.

A lever 23 pivotally mounted at a point between its ends on an ear 27extending from the casing 16 and operatively connected at one end withthe movable abutment as indicated at 22 serves to transmit the action ofthe governor to any suitable speed controlling device which may beconnected at the other end.

The operation of the governor is similar to that of the regulator ofFigs. 1 and 2 in that it operates only when normal operation is departedfrom to a certain predetermined degree in either direction. That is, thefly weights 59, 59 revolve in the same position relative to each otherregardless of speed changes between a certain higher limit and a certainlower limit of speed, but when the higher limit is reached the tensionof the spring 19 is just balanced by the centrifugal force then actingon the weights 59, 59, the movable abutment is on the point of leavingcontact with the stop disk 2-9 and any further increase in speed willcause the fly weights to move carrying said abutment 18 with them. Thisin turn moves the lever 23 to effect the proper change in the controldevice, for example, to reduce the speed.

As the speed falls below the upper limit, the balance between spring 19and the centrifugal force acting on the fly weights is destroyed withthe result that the movable abutment is forced against the stop disk 29by the spring 19 with increasing force until the lower limit of speed isreached. The auxiliary spring plus the centrifugal force then exerted onthe fly weights 59, 59 just balance the force of the spring 19 The stopdisk is just on the. point of leaving the stop shoulder 30. Any furtherdecrease in speed will cause the auxiliary spring to yield and permitthe movable abutment 18 to be moved downwardly, resulting in theoperation for example, of a speed controlling device through the lever23 to correct this tendency to fall below the lower limit.

It will be understood that this is but one application of the inventionto speed controlling devices, and that the invention is not confined toany particular applications herein described and illustrated, but may becarried out by other means to meet any particular need for a limitregulator.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In a limit regulator, the combination of a movable abutment having acertain range of travel, means providing a variable and a constantlyacting force to move the abutment in one direction operatively connectedwith said abutment, stop means limiting the action of the constantlyacting forceto less than the full travel of the motable abutment, meansproviding a second constantly acting force to move the abutment in theopposite direction, and control means operatively connected with saidmovable abutment to be actuated by movement thereof.

2. A regulator operated by and controlling a varying force-through amovable member embodied in its structure, said regulator beingcharacterized by the fact that its movable member is held stationarybetween certain predetermined higher and lower limits in the magnitudeof the varying force.

3. The combination with a governing mechanism, of a regulator comprisinga movable member connected with and con trolling said mechanism, meansproviding a varying force controlled by the governing mechanism to acton the member to move it, means preventing movement of the member in onedirection when the magnitude of said force is of a value below a certainpredetermined higher limit, and an auxiliary means preventing movementof the member in the opposite direction when the magnitude of said forceis of a value above a cer tain predetermined lower limit.

4. A regulator comprising a movable member, means providing a constantlyacting force and a variable force to act thereon in opposition, thevariable force being normal: 1y less than the first named force wherebythe member is normally biased in the direction of said variable force,means providing an auxiliary force to act supplementary to the variableforce to balance the member against the constantly acting force as thevariable force assumes any value between a certain higher predeterminedlimit at which the latter force alone equals the first-named force and acertain lower predetermined limit at which the variable force and theauxiliary force combined equal the first named force whereby the memberis held stationary between said limits, means preventing thesupplementary action of the auxiliary force when the variable forceassumes a value at and above the predetermined higher limit whereby themember is moved by the variable force as it exceeds said limit andbecomes greater than the constantly act mg force, said auxiliaryforce'being set to ill) yield to the constantly acting force as thevariable force falls below the predetermined lower limit whereby themember is moved by the constantly acting force, and control meansoperatively connected with the movable member to be actuated by itsmovement.

in combination, a movable member, means biasing said member in a certainpositive direction, means providing a variable force to bias the movablemember in an opposite negative direction, said first-named means beingset to yield to the opposing variable force when the latter passes abovea predetermined higher limit whereby the member is moved in saidnegative direction, said first-named means being normally superior tothe variable force, whereby the member is normally biased in thefirst-named positive dir ction, auxi iary means provided to act upon themovable member in conjunction with and supplementary to the variableforce, said auxiliary means so acting only when the variable -forcefalls below the higher predetermined limit to hold the movable memberstationary from moving in the positive direction, said auxiliary meansbeing set to yield when a certain predetermined lower limit is reachedby the variable force and to permit the member to be moved in thepositive direction through action of the first-named means, and meanspreventing the supplementary action of the auxiliary means when thevariable force assumes a value at and above the predetermined higherlimit.

6. In combination, a movable member, means biasing said member in acertain positive direction, means providing a variable force to bias themovable member in an opposite negative direction, said first-named meansbeing set to yield to the opposing variable force when the latter passesabove a predetermined higher limit whereby the member is moved in saidnegative direction,

'said fiISt-l12tlllG(l means being normally superior to the variableforce, whereby the member is normally biased in the first-named positivedirection, auxiliary means provided to act upon the movable member inconjunction with and supplementary to the variable force, said auxiliarymeans so acting only when the variable force falls below the higherpredetermined limit to hold the movable member stationary from moving inthe positive direction, said auxiliary means being set to yield when acertain predetermined lower limit is reached by the variable force andto permit the member to be moved in the positive direction throughaction of the firstnamed means, a device for controlling the value ofthe variable force, and means connecting the movable member with saidcontrolling device such that a movement of the member in the positivedirection will cause a corresponding increase in the variable a valuedetermined by its speed, of a regulator controlling its speed,comprising a movable member upon the position of which the speed of thecompressor depends, means biasing said member to a position to increasethe speed, means supplying pressure from the discharge conduit of thecompressor to bias the member to a position to decrease the speed, saidfirst-named means preventing movement oi the member by the pressuresupplied by-said secondaiamed means until the latter exceeds a certainpredetermined higher limit, and an auxiliary means preventing movementof the member by said first-named means until the pressure supplied bysaid sccondnamed means falls be low a certain predetermined lower limit.

8. Tie c niibination with a centrifugal compressor or the like and adevice for controlling its speed, oil a pressure regulator comprising amovable member operativcly connected with the speed controlling device,means supplying pressure delivered by the compressor to act upon themember to move it, means preventing movement of the member below acertain predetermined higher limit of said pressure and an auxiliarymeans preventing movement of the member above a certain predeterminedlower limit of said pressure whereby said member is held stationary andthe speed controlling device inoperative while the pressure supplied bythe compressor remains between said limits. 9. The combination with acentrifugal compressor or the like having a discharge conduit and anassociated mechanism for controlling its speed, of a pressure regulatorforming an operative connection between said mechanism and the pressuresupplied by the compressor to said discharge conduit and comprising amovable member con nected with said mechanism to operate the same by itsmovement, means supplying pres sure from the compressor dischargeconduit to the movable member to bias said member in a direction tolower the speed through the controlling mechanism, means supplying anormally superior force biasing said member in the opposite direction toraise the speed through the controlling mechanism, said last-named meansbeing set to yield to the biasing action of pressure supplied from thecompressor discharge conduit when said pressure passes above a certainpredetermined higher limit whereby the member is moved and the speedreduced, an auxiliary means providing a supplementary force to act onthe movable member in conjunction with the pressure supplied from thecompressor discharge conduit when the latter falls normally below thepredetermined higher limit to hold the movable member against thebiasing action 01": the first-named means, said. lastnamed auxiliarymeans being set to yield to the force of the firstnamed means when thepressure supplied from the conduit falls below a certain predeterminedlower limit and permit the member to be moved in a direction to raisethe speed through the controlling mechanism.

1.0. In a limit regulator, the combination with a movable abutment, ofmeans provid ing a variable force, the magnitude of which is to beregulated, to act thereon to move it, means providing a biasing fiercecontinually acting upon the abutment to move it in opposition to saidfirst-named iorce whereby said abutment tends to be moved to positionswherein a balance is ell ected between said opposing forces, the valueof the biasing force being such that the abutment is in a balancednormal position when the variable force assumes a certain predeterminedhigh value, a yieldable stop means for the abutment which receives thethrust of the biasing force when the variable force falls below saidpredetermined high value, said step means being set to yield and permitthe abutment to move when the variable force falls below a certainpredetermined low value, and control means for said variahis forceoperatively connected with the abutment to be actuated by movementthereof.

11. In a limit regulator, the combination with a movable abutment, ofmeans provida variable force, the magnitude of which is to be regulated,to act thereon to move it,

.a spring connected with said abutment to move it in opposition to saidvariable force, whereby said abutment tends to be moved to positionswherein a balance is eil ected between the variable force and that setupby the spring, said spring being adjusted to provide a force equal to acertain predetermined high value of the variable force when the abutmentis in a certain normal position, a second spring providing a stop meansfor the abutment to hold the same immovable when the variable forcefalls below the predetermined high value and being set to yield andpermit the abutment to move when said variable force falls below acertain predetermined low value, said last-named spring beingoperatively disconnected from the abutment when the variable forcereaches and exceeds said predetermined high value, and control means forthe variable force operatively connected with the abutment to beactuated by movement thereof.

In witness whereof, I have hereunto set my hand this 7th day of May,1923.

THEODOR STEIN,

